I would stick with the AR-7 if you are planning any long distance stuff: 1. 22LR is amazingly accurate and efficient. I carried an Armalite AR-7 as my main pack gun when I used to go on long distance hikes and used to carry it assembled, using a bootlace as a sling and carrying fishing line, bandaids, spare ammo and a compass in the butt. I could shoot any and all rattlesnakes and if I outran my food supply, quail and occasionally trout near the surface supplied the protein. 2. You can carry a huge amount of .22 ammo! 3. The AR-7 is dependable, very light, and semiauto - and there is a decent Ramline magazine out there that carries 15 or so rounds.
Now, if you absolutely have to have something heavier, there's always the Savage Model 24 .22LR over .410 or .22LR over 20 gauge Magnum or .222 over 20 gauge and a couple of other variations.
All of your info is very good.
A long hike can weigh heavy on your mind, as well as on your body.
I haven't made my purchase yet, so I'll give your words some thought.
I've read that most bear encounters along the trail are a "stand still and allow the bear her room, and eventually she'll leave" situation.
But rarely someone will walk up on one in dense undergrowth and have a real problem.